There are many instances where the need for temporary, portable toilet facilities is desirable. Events such as fairs, concerts, and the like often make use of portable facilities. Campgrounds and similar locations may use a “pit” toilet, while not being portable is also not flushable.
In these cases where the waste is not flushed away into a remote sewer or septic system, the situation is likely to occur where the refuse collecting in the tank is visible to the users. This is obviously an unsightly situation, as well as creating odor and possibly leading to an unsanitary situation. Indeed, it is possible that some of the waste already collected in the tank may splash upward and contact a person using the portable toilet—an unacceptable possibility.